The invention relates generally to an exhaust gas recirculation system and more particularly to a system and method for waste heat recovery from the recirculating exhaust gases.
Generally, the exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique in internal combustion engines such as diesel engines or petrol/gasoline engines. NOx forms primarily when a mixture of nitrogen and oxygen is subjected to high temperature within a combustion chamber of the engines. High amounts of nitrogen oxides (NOx) emissions in atmosphere causes air pollution leading to formation of smog and adversely affecting the environment. In an EGR system, a portion of the exhaust gas is recirculated through piping from an exhaust manifold to an inlet manifold of the engine. This involves cooling the exhaust gas, mixing with an intake air and finally recirculating back into the engine through the inlet manifold. The cooling of the exhaust gas is important to ensure low emissions and maintain good efficiency of the engine. Further, the cooling of the exhaust gas is predominantly done using an EGR cooler, which EGR cooler is a heat exchanger. Generally, the EGR cooler uses water or ambient air to draw heat from the flow of hot exhaust gas. This leads to wastage of energy and without reduction in fuel consumption.
Accordingly, there is an ongoing need for recovering the heat form the recirculating exhaust gases to derive useful work.